A. Field of the Invention
The present invention relates generally to apparatus for cutting cylindrical articles such as trees or underwater piles, or the like, and more particularly to a shear blade cutting apparatus having means for adjusting blade alignment and compensating for wear.
B. Description of the Prior Art
Shear blade cutting devices have been developed for cutting cylindrical wooden articles. For examples, in U.S. Pat. No. 4,168,729, there is disclosed a shear blade device for cutting underwater piles. In U.S. Pat. No. 3,640,322, there is disclosed a similar shear blade device for cutting trees.
Both the devices of U.S. Pat. Nos. 4,168,729 and 3,640,322 patents include a frame assembly having a pair of shear blades pivotally mounted thereto. Powerful hydraulic actuators are provided for moving the shear blades in pincer-like fashion with respect to each other.
In order to effectively cut the tree or pile, it is necessary that the shear blades substantially meet each other when the cutting device is enclosed, but it is also important that the shear blades do not overtravel each other. The apparatus of the U.S. Pat. No. 3,640,322 provides for blade alignment and prevents overtravel by including a heavy rib about the edges of the shear blades. The ribs act as a stop and allow the blades to travel toward each other until they just meet.
There are a number of shortcomings associated with the shear blade cutting apparatus of the prior art. Neither the apparatus of the U.S. Pat. No. 4,168,729 nor of the U.S. Pat. No. 3,640,322 has any means for compensating for wear of the blades or other parts of the apparatus during use. If the blades of, for example, the U.S. Pat. No. 3,640,322 apparatus become damaged to the extent that they do not meet when the stops formed by the ribs engage each other, the blades must be replaced. Also, in either the apparatus of the U.S. Pat. No. 4,168,729 or U.S. Pat. No. 3,640,322, if the connections between the various parts become worn such that the blades do not meet, it is necessary to overhaul the apparatus completely.
It is therefore an object of the present invention to provide a shear blade cutting device that overcomes the shortcomings of the prior art. More specifically, it is an object of the present invention to provide a shear blade cutting device having means for adjusting blade alignment and compensating for wear of its various parts.